Oh my, something magical has happened to my SDA's

nspindel

nms wrote: »

I'm sure this has been asked and answered before, but is the RD0-198 / TL upgrade significantly better than the RD0-194 tweeter, and if so, why? Thanks.

Yes. Because

To be honest, I can't say why the tweeter in and of itself is better. To use it you need that extra 5.8uF cap, and I don't know what impact that cap has on the overall presentation (as opposed to the tweeter in and of itself). All I can say is that I'm very impressed.

ben62670

Sweet Enjoy:)

heiney9

Would we steer you wrong? Nice write up and you will be in for a treat over the next 300-400 hours.

This is a no brainer for older speakers like this and the cost while a large amount is still considerably less than new speakers.

One can even gain a huge improvement by doing non-SDA speakers too. I did a pair of Monitor 5b's which I use in my office rig and they turned out phenomenal. My 1C's are superb with the upgrades too.

H9

nspindel

heiney9 wrote: »

Would we steer you wrong?

Nope!

Although F1, I thought you said the Sonicaps were blue???

MillerLiteScott

Nice job and write up. Last night I did a speaker switcheroo and listen to my pair of 2B TL's, Stock 1C's and RTA 11t's with RDO 194. The TL version has much better high end than the other two by leaps and bounds. The other speakers sound congested in comparrison. Surprisingly my RTA 11T's seem to have stronger, deeper bass.

Enjoy your TL's.

Scott

danger boy

nice work and good write up.. i think a ways down the road this may be the next step for me too.

nspindel

Only thing left to do on these speakers is to get them re-veneered one day.

Long story short, I originally had a pair of SDA-CRS+'s that I got in college back in 1989. I wanted to buy the 2B's, but they were too big for my dorm room at the time. The CRS's were great, but the 2B's have more oomph, just because of the size and bigger passive radiator. About 3 years ago, I saw these 2B's come up for $200 buy-it-now on eBay - relatively cheap because the shipping cost would be crazy. But they were in NYC, and I'm only about 40 miles away. So I grabbed them and picked them up in person. Then I sold my CRS+'s to a guy at work for.... $200. So I got a free upgrade to the speakers I wished I had bought from day one. Only problem with them was that the veneer is a bit chipped along the back edges, probably the result of the original owner moving from apartment to apartment to apartment in NYC. Nothing terrible, they're not screaming to be re-done or anything. But considering the upgrades I just did, I've turned these things into speakers for life. I want them to look as pretty as they sound. So at some point in the not too distant future I'll find a wood shop that can make the outsides up to par with the insides!

nspindel

I'm in Connecticut.

nspindel

I cut them round - I don't understand the fuss over the shoulders on the posts. The posts come with a nylon shoe that the posts sit in. The shoe is formed for the shoulders on the post. The back of the post protruding from the shoe is perfectly round. I think I used a 3/8" drill bit. The cardas posts don't come red/black, they're both identical. There's a small, hard to read +/- indication on the shoe though. If you don't want the black shoe and would rather have something that indicates red/black, Cardas makes insulators that also accept the shoulder, colored red and black:

http://www.cardas.com/content.php?area=oem&pagestring2=Insulators&pagestring=Insulators+(closeup)&content_id=14&part_id=63

Looks like those have shoulders on the back as well. If you use the shoe that the posts come with, then the two are held together, so they can't spin. If you use those insulators, then you can have some spin. So I guess this is an issue on my SDA interconnect post, but I hot glued the back and tightened the nut reasonably snug. I wasn't concerned enough about it to start trying to cut those shoulders into the Polk plastic with a rotary tool.

Windwalker

nspindel wrote: »

Only thing left to do on these speakers is to get them re-veneered one day.

... So at some point in the not too distant future I'll find a wood shop that can make the outsides up to par with the insides!

Are you going to leave as cloth sides or are you thinking about having the sides done in wood?

I recently acquired some 2Bs as well and am thinking about possibly taking the cloth sides off and re-doing with a veneer insert

nspindel

Windwalker wrote: »

Are you going to leave as cloth sides or are you thinking about having the sides done in wood?

I recently acquired some 2Bs as well and am thinking about possibly taking the cloth sides off and re-doing with a veneer insert

Cloth sides??? My sides are solid with the same veneer as the top.

heiney9

nspindel wrote: »

Cloth sides??? My sides are solid with the same veneer as the top.

You have the studio version. The cab construction and materials are a little different, as was the original price. The studio versions were less expensive. The studio versions weighed 65lbs and the regular version weighed 80lbs

H9

Windwalker

Yea what H9 said
realized that yours where the studio version, right after I went back and looked at your picture-oops, sorry

SCompRacer

Good job! Nice pics! High marks!

Njoy.

nspindel

Ah.....

F1nut

I cut them round - I don't understand the fuss over the shoulders on the posts. The posts come with a nylon shoe that the posts sit in.

Some of us prefer a more polished look when installing the Cardas binding posts, taking the time and effort or fuss as you state, to do it right by fitting them without the nylon shoe.

nspindel

Mmmmm... That does look nice!!!

agfrost

nspindel wrote: »

Like I said, I'm no Mark Twain when it comes to describing this stuff. But the tweeter makes a huge difference, and I'm coming from the 194, not the plastic dome. The vocals sound much more real, cymbols resonate a lot more, and there's much more detail to the highs. The bass is phenominal. I'm finding that lower-volume listening is much more rewarding. Cranking it up is hugely fun, but I can still hear (and feel) some great bass at lower volume. The "punchiness" is much improved, and there's a lot more reality to the music.

Eh, I read Mark Twain's writeup from when he rebuilt the crossovers and picked up the RDO tweeters, it wasn't all that. No need to sell yourself short.

Congrats on taking the plunge and doing the rebuild. I'm considering redoing my RTA 11TLs at some point, and every satisfied rebuilder that posts here adds fuel to that fire.

Keep posting as you log more hours on 'em!

Jay

wingnut4772

OldmanSRS

nspindel wrote: »

When I first powered everything up after the mods, it didn't sound all that great. I wasn't expecting it to. The threads talking about these mods all warn that initial response is surprisingly poor, and that break-in time is an absolute necessity. At first, the highs were quite tinny and the bass was extremely thin. However, I was expecting this to last a long time - it's been detailed that these mods can take 200-400 hours to burn in. This may well be the case, but the amount of improvement that happened in the first 2 hours was incredible. I've got (maybe) 5 hours on them now, and if they're just going to keep getting better from here, then I'm in for a real treat....

Ok, so that's it for the intro first post. Next come some pictures!

I'm naturally a skeptic so excuse that about me for a moment. I just have to ask how a burn-in will improve the bass sound characteristics of this speaker when all that changed was the inductor that rolls off the highs to the mid woofers. An inductor is a coil of wire. It's very electrically stable. If the sound improved, then it must have changed electrically and if that's the case it could have changed for the worse as well. Rarely in electronics do passive components change at all, or change for the better with age or use.

I can see how changing the tweeters could be the largest improvement here. Changing the tweeters mandated changing some caps and resistors, which could be an improvement. Maybe the bass sounds better because it's now a better fit, more in balance, with the quality and tone of the new tweeters?

I have the original SRS's and may change the tweeters at some point if I can justify the expense.

Flame on.
Greg

heiney9

OldmanSRS wrote: »

I'm naturally a skeptic so excuse that about me for a moment. I just have to ask how a burn-in will improve the bass sound characteristics of this speaker when all that changed was the inductor that rolls off the highs to the mid woofers. An inductor is a coil of wire. It's very electrically stable. If the sound improved, then it must have changed electrically and if that's the case it could have changed for the worse as well. Rarely in electronics do passive components change at all, or change for the better with age or use.

I can see how changing the tweeters could be the largest improvement here. Changing the tweeters mandated changing some caps and resistors, which could be an improvement. Maybe the bass sounds better because it's now a better fit, more in balance, with the quality and tone of the new tweeters?

I have the original SRS's and may change the tweeters at some point if I can justify the expense.

Flame on.
Greg

Your allowed to have skepticism but in all honesty if you have never tried any of these upgrades then your opinion really doesn't have any validity. Most who refresh their x-overs hear an instant and identifiable difference and this difference gets better over time as parts burn in.

If you are at all handy with a soldering iron give it a try along with the new tweets and you'll be extremely happy. I have (2) pairs of refreshed Polks; SDA 1C's and Monitor 5b's and the improvement is dramatic and extremely positive.

You can certainly continue to doubt but unless you given it a try then you really have no basis to acknowledge that the results aren't true.

H9

Schurkey

So, where can I find a thread like this as a guide to modifying/upgrading a pair of SDA 1B crossovers?

I tried some searches, but got nothing useful.

danger boy

i don't think you can modify the SDA 1B's to the same level as the 2B's that nspindel did. yes you can update the caps and resistors in your speakers crossovers, which will help. and you can also update the tweeters as well. but i don't think a mod to the 4.1TL level is possible with your version of speaker.

dbnh

Windwalker wrote: »

Yea what H9 said
realized that yours where the studio version, right after I went back and looked at your picture-oops, sorry

I like the studio version, something compellingly right about the all black, at least to my aesthetic. Anyway, nice job and thanks for the input on your upgrades. [FYI - I was going to have my crossovers redone by someone but that's fallen through due to health issues with the person's family. So, if there's anyone in NH who's interested in upgrading some 1C crossovers, please drop me a PM.]

heiney9

danger boy wrote: »

i don't think you can modify the SDA 1B's to the same level as the 2B's that nspindel did. yes you can update the caps and resistors in your speakers crossovers, which will help. and you can also update the tweeters as well. but i don't think a mod to the 4.1TL level is possible with your version of speaker.

You are correct DB. The 2B's have the same crossover as the CRS+ and those are the only models that can take advantage of 4.1TL mod.

Upgrading caps in other SDA model's is highly recommended as well as replacing tweeters with the RD)'s.

H9

OldmanSRS

H9,
I really didn’t expect this kind of response from you or anyone here. When you state “that my opinions have no validity”, who the heck are you to decide that? You know nothing of my engineering, electronic, scientific, or audio experience and background. I was hoping for an adult response by someone who could share some useful opinions and data regarding my questions.

If you re-read my post, you will see that I ask two specific questions: “I just have to ask how a burn-in will improve the bass sound characteristics of this speaker when all that changed was the inductor that rolls off the highs to the mid woofers.”

AND

“Maybe the bass sounds better because it's now a better fit, more in balance, with the quality and tone of the new tweeters?”

I also stated some facts: “An inductor is a coil of wire. It's very electrically stable. If the sound improved, then it must have changed electrically and if that's the case it could have changed for the worse as well. Rarely in electronics do passive components change at all, or change for the better with age or use.”

You stated “You can certainly continue to doubt but unless you given it a try then you really have no basis to acknowledge that the results aren't true.” I did not question the positive result of this upgrade, only the mechanism at work during a burn-in that would remedy “extremely thin bass”.

Now I’m going to state some opinions. The inductor change that reduced the original low pass inductor’s resistance value from 3.2 Ohms to the new inductor’s value of 0.5 Ohms should have a big impact on the current reaching the MW. Picking 20 Hz as an example frequency, the inductive reactance of the old and the new 15mH inductors are both equal at 1.9 Ohms. Adding the DC resistance (3.2 Ohm) to the inductive reactance (1.9 Ohm) the calculated total impedance at 20Hz is 5.1 Ohms. The new inductor at the same frequency has a much lower 2.4 Ohm total impedance. The lower impedance of the new inductor will potentially allow more current to flow through the rest of the low pass filter circuit into the MW. Of course, any potential current increase depends on the impedance values of the other components in the low pass circuit, the circuit’s resonant frequency, and the true impedance of the MW voice coil. The inductor’s lower impedance should produce stronger bass without altering the crossover point and that seems completely opposite to what nspindle describes as hearing “extremely thin bass”.

If you have an explanation as to why the bass was described as thin, but after 2-3 hours of burn-in, “The bass is phenominal. I'm finding that lower-volume listening is much more rewarding. Cranking it up is hugely fun, but I can still hear (and feel) some great bass at lower volume. The "punchiness" is much improved, and there's a lot more reality to the music.”, you could chime in now.

That brings me back to my second question: “Maybe the bass sounds better because it's now a better fit, more in balance, with the quality and tone of the new tweeters?”

And now the last questions which are actually a refinement and expansion of my second question: Does anyone agree that since the new tweeters are electromechanical dynamic devices, their tonal quality could have altered in a beneficial way by virtue of several hours of operation (voice coil and diaphragm excursion) and become less as described “the highs were quite tinny”? If so, is it then plausible that the bass is perceived as better after several hours of operation and the highs more pleasing, contributing to the overall sonic improvement in terms of lows and highs people are describing with this upgrade?

I we all can't share ideas, theories, and opinions here equally, what's the point?

heiney9

OldmanSRS wrote: »

H9,
I really didn’t expect this kind of response from you or anyone here. When you state “that my opinions have no validity”, who the heck are you to decide that? You know nothing of my engineering, electronic, scientific, or audio experience and background. I was hoping for an adult response by someone who could share some useful opinions and data regarding my questions.

Sorry if I offended you, wasn't my intent at all. To put my comment in perspective I simply meant that if you haven't replaced cross-over components or tweeters in your SRS's you can't make an informed comment about whether it makes a difference or not. Perhaps I read too much into your initial post and then made an incorrect inference about your intent and knowledge. I apologize if my comment offended, it wasn't meant to have a harsh tone.

As for your questions, they are valid and since I really have no scientific background I can't answer the "why" part. This is a highly debated area of audio and there is little hard measurable corollary scientific evidence to answer the "why" part.

I tend to rely on the tried and true method (for me) to let my ears decide. One could duplicate certain experiments over and over in a different environment and with different sets of ears and come up with responses all over the place. I've never been one just to look at measurements/specs. etc. to decide if something makes a difference or not.

I've been in situations where a certain thing shouldn't make a difference but it does and I've been in situations where something should make a difference and it doesn't.

Hopefully some of the more technical/scientific people will chime in.

H9

nspindel

The new inductor measures .5 ohms, not .15.

Other than that, I'm keeping out of this - I've got the speakers and the ears, that's all I need....

F1nut

OldmanSRS wrote: »

I just have to ask how a burn-in will improve the bass sound characteristics of this speaker when all that changed was the inductor that rolls off the highs to the mid woofers.

That one inductor wasn't the only component that was changed. All the original caps and one resistor were changed to superior film and foil caps and an non-inductive resistor with one new cap added for the different tweeter. I've not replaced any inductors in my mods, yet the bass improvement is quite noticeable and kept improving thoughout the burn-in process.

nspindel

On a side note....

I'm at about 50 hours now. These speakers ought to be illegal. I just can't believe how good they sound. Just listened to Tull - Locomotive Breath off the Mobilie Fidelity remaster of Living in the Past. It almost lifted me out of my seat.